Re: Radar Detection Of UFOs

From: Peter Davenport <director.nul>
Date: Fri, 13 May 2011 06:37:06 -0700
Archived: Fri, 13 May 2011 13:28:57 -0400
Subject: Re: Radar Detection Of UFOs
>From: Martin Shough <parcellular.nul>>To: <post.nul>>Date: Thu, 12 May 2011 18:37:21 +0100>Subject: Re: Radar Detection Of UFOs>>From: Ralph Howard <rhjr.nul>>>To: post.nul>>Date: Thu, 12 May 2011 08:55:27 -0700 (PDT)>>Subject: Radar Detection Of UFOs [was: SETI Summary]>><snip>>>Concerning radar detection, just an FYI for everyone's use... In>>looking into the potential for use of NEXRAD weather radar data>>in UFO sighting investigations, I recently found that there is a>>"scientist and meteorite hobbyist", a Ph.D. fellow at the>>Planetary Science Institute in Tucson AZ, who runs a>>blog/website devoted to providing NEXRAD weather radar data as>>a resource for finding meteorites. Additional quotes from Dr.>>Marc Fries' blog:>>http://radarmeteorites.wordpress.com/>>"It turns out that Doppler weather radars are a valuable resource>>for not only finding meteorites from fresh falls but also for>>studying the dynamics of the fall itself. In the US, the NEXRAD>>radar network operated by NOAA provides continuous coverage of>>most of the US landmass. Any meteorites that fall here have to>>fall through airspace that is monitored by NEXRAD, and when the>>conditions are right we can spot them on the way down.">Thanks, Ralph, very interesting. I'm surprised that NEXRAD is>thought to have much of a role here, though, because coverage is>so restricted.>The NEXRAD uses a narrow 1-degree pencil beam and a selection of>different scan algorithms to build up coverage in a series of 1->degree slices at a ponderously slow rate, between about 5 and 10>_minutes_ depending on mode. This compares with a typical>surveillance radar that fills the same scan volume in as many>_seconds_. (Of course they aren't looking for primary targets>like meteors, but you get the point). The most sensitive (clear>air) NEXRAD mode only covers the sky up about 4 or 5 degrees>elevation anyway, and the less-sensitive precip[itation modes>still only go up to about 19 degrees and take 5 or 6 minutes to>do it.>So I should have thought that even with overlapping coverages the>chances are very small of spotlighting a useful number of>1-degree pieces of meteor trail so as to build up a track - when>a typical trail is gone in seconds . And the wavelength is short>, too - 10cm S-band - not ideal for ionisation returns, which are>favoured at very long wavelengths.><snip>>>... keeping up with this website makes a lot of>>sense, because of the potential for NEXRAD recording something>>anomalous.>It is intriguing. I want to take a closer look. Thanks for the>tip.>Martin Shough
Ralph and Martin,
Thank you both for your informed and edifying comments about the
NEXRAD radar system. I learned a great deal about that system
from what the two of you have written above.
The principal shortcoming of that type of "active" radar for
detecting short-lived, and high-velocity, targets is as Martin
describes... the system might not detect them at all. Therein
lies the advantage of using a "passive" radar system, which
detects targets in all directions simultaneously, and does so on
a virtually continuous basis. An "active" radar radiates a thin
"pencil" of electromagnetic radiation, which "sweeps" a target
intermittently, which can be defeated easily; a "passive" system
radiates in all directions, and does so as long as the signal of
choice is being transmitted. For details of such a system, I
would recommend a search of the web for the "Naval Space
Surveillance System," which uses a 742,000 watt "passive"
system, based in Lake Kickapoo, Texas.
I believe that the "passive" system I describe in my paper
proposes a system that sidesteps the shortcomings of an "active"
system, for reasons that Martin correctly identifies in his
comments above.
I am just leaving for the McMinnville, Oregon, conference, but
will respond to any comments, upon my return.
Peter
NUFORC
Listen to 'Strange Days... Indeed' - The PodCast
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